Method and apparatus for preventing adherence of solid products in gas exhaust pipe and exhaust gas abatement device with same apparatus

ABSTRACT

A solid product removal method for removing a solid product adhering to a gas exhaust pipe member having a rinsing water inlet pipe member with a tip opening located inside the gas exhaust pipe member for feeding rinsing water into the inside of the gas exhaust pipe member from the tip opening thereof; hence a solid product formed newly upon reaction with the rinsing water and adhering thereto can be rinsed off with the rinsing water introduced from another tip opening located at a different position; and therefore, an adherence of the solid product can be prevented from heating the inner face of the gas exhaust pipe member. A scraping member for scraping the solid product stuck to the inner face of the gas exhaust pipe member may be used.

TECHNICAL FIELD

The present invention relates to a method and an apparatus forpreventing adherence of a solid product in a gas exhaust pipe memberand, more particularly, to a method and an apparatus suitable forpreventing adherence of a solid product in a gas exhaust pipe member forleading an exhaust gas discharged from a semiconductor manufacturingapparatus to an exhaust gas abatement device.

BACKGROUND TECHNOLOGY

FIG. 17 illustrates a layout of a general-type exhaust gas removalapparatus for a semiconductor manufacturing apparatus. In asemiconductor manufacturing apparatus 100, semiconductor substrates areprocessed using a variety of processing gases in a vacuum chamber 102,and the processing gas is discharged from the vacuum chamber 102 with avacuum pump 104 and fed to an exhaust gas abatement device 106 connectedto a downstream side (an outlet side) of the vacuum pump. The hazardousgas is then processed to become a non-hazardous gas that in turn is fedto an gas exhaust duct 108. As the exhaust gas contains an ingredienthaving a low vapor pressure at ambient temperature, it may becomesolidified at the time when the pressure downstream of the vacuum pump104 elevates, and may then adhere to an exhaust pipe member and becomedeposited thereonto. For instance, such an ingredient may include but isnot limited to aluminum chloride (AlCl₃) discharged in an etchingprocess for aluminum wiring, ammonium chloride (NH₄Cl) derived in aprocess for forming a film of silicone nitride (SiN) or titan nitride(TiN), and tetraethyl silicate (TEOS) used in forming a film of siliconeoxide (SiO₂).

Further, the exhaust gas may contain an ingredient that may produce asolid product upon reaction with water. For instance, such an ingredientmay include but be not limited to BCl₃ to be used in etching foraluminum wiring, and SiCl₄ to be discharged upon etching a polysiliconwith a Cl-type gas. These solid products may be stuck to an exhaust pipemember close to an inlet of the exhaust gas abatement device anddeposited thereon because humidity in the gas exhaust pipe memberbecomes high in the case where the exhaust gas abatement device is of awet type using water for the removal of a hazardous ingredient.

The adherence and deposit of the solid products in the pipe member maybe generally prevented, for example, by winding an exterior portion ofthe gas exhaust pipe member for flowing exhaust gas with a heater andheating the gas exhaust pipe member or other processes.

The gas exhaust pipe member, however, is provided, for example, with avariety of valves or branch pipe members and a bypass pipe memberconnecting an upstream side (an inlet side) to a downstream side (anoutlet side) of the exhaust gas abatement device, and so on, and thepipe construction may be rendered complex at many points, and thus itbecomes difficult to wind the heater around the pipe member as a wholein an appropriate fashion. Therefore, problems may result, for instance,that a solid product may adhere to and deposit inn a valve unlikely tobe heated or that a solid product may adhere to a portion of the pipemember where flow of an exhaust gas may slow due to a complicated pipeconstruction. Moreover, in the case where the exhaust gas abatementdevice for processing exhaust gas into a non-hazardous gas is of a wettype where the exhaust gas is brought into contact with water, ahumidity may become too high at a portion of the pipe member close tothe inlet of the exhaust gas abatement device, whereby it may becomeimpossible to heat the portion thereof to a sufficiently high degree. Inparticular, in the case where the exhaust gas contains an ingredientproducing a solid product upon reaction with water, it may present theproblem that the solid product formed due to such a high level ofhumidity is likely to adhere to and deposit on the portion of the pipemember.

In view of the foregoing problems, the present invention has been madewith the object of providing a method and an apparatus for preventingadherence and deposit of a solid product in a gas exhaust pipe memberfor discharging exhaust gas.

DISCLOSURE OF THE INVENTION

The present invention provides a solid product removal apparatus forremoving a solid product adhering to an inner face of a gas exhaust pipemember, which is characterized by a rinsing water inlet pipe member witha tip opening disposed at the tip of the gas exhaust pipe memberpositioned therein so as to feed rinsing water from the tip opening tothe inner face of the gas exhaust pipe member. The term “rinsing waterinlet pipe member” referred to herein includes not only a single pipemember simply for introducing rinsing water, but also a means forallowing rinsing water to flow from the outside into the inside of thegas exhaust pipe member, including a hole disposed through a pipe wallof the gas exhaust pipe member, which can receive the rinsing water fedfrom a pipe member for introducing the rinsing water into the inside ofthe gas exhaust pipe member and allow the rinsing water to pass thereto.

The solid product removal apparatus is useful particularly with anexhaust gas containing an ingredient forming a solid product uponreaction with water present in the gas exhaust pipe member, since it isable to wash off the solid product formed and stuck to the inner face ofthe pipe member with a rinsing water.

The rinsing water inlet pipe member may be disposed on a periphery ofthe gas exhaust pipe member and provided with a ring-shaped rinsingwater jacket member receiving rinsing water. The tip opening at the tipof the rinsing water inlet pipe member may be formed as a plurality ofholes communicating with the rinsing water jacket member and furtherwith the pipe wall of the gas exhaust pipe member and extending into theinside of the gas exhaust pipe member (disposed in a relationship spacedapart at given intervals in a peripheral direction of the gas exhaustpipe member).

More preferably, a heating means for heating the gas exhaust pipe membermay be provided to evaporate rinsing water remaining in the inside ofthe gas exhaust pipe member by heating after introduction of the rinsingwater. This is to prevent any fresh solid product from being formed withthe rinsing water remaining in the inside of the gas exhaust pipemember.

The rinsing water inlet pipe member may be disposed in plural numbers,and the tip openings of the rinsing water inlet pipe members may beformed at a spaced relationship at predetermined intervals along a flowpath of exhaust gas in the gas exhaust pipe member. This structureallows a fresh solid product formed and stuck upon reaction with rinsingwater in the gas exhaust pipe member to be washed off with rinsing waterintroduced from a tip opening or openings at a different position orpositions, when a solid product formed and adhering upon reaction withwater in the gas exhaust pipe member is washed with rinsing waterintroduced from the tip opening at a given position. It is to be noted,however, that a single tip opening can perform a similar rinsing action.This can be done by changing a range of distribution of rinsing water byadjusting a pressure of discharging rinsing water from the tip opening.From this point of view, the present invention can also provide a methodfor rinsing a solid product in the manner as described above. Morespecifically, this method is characterized by a step of rinsing off aprimary solid product formed upon reaction with moisture contained in anexhaust gas present on the inside of the gas exhaust pipe member byfeeding a primary rinsing water, and a step of rinsing off a secondarysolid product formed freshly upon reaction with the primary rinsingwater adhering to the inside of the gas exhaust pipe member by feeding asecondary rinsing water.

Further, the present invention provides a solid product removalapparatus for removing a solid product stuck on an inner face of a gasexhaust pipe member, characterized by a high-temperature gas inlet meansfor heating the inside of the gas exhaust pipe member by introducing ahigh-temperature gas having a high temperature in the gas exhaust pipemember. Heating the inside of the gas exhaust pipe member may prevent adeposit of a solid product. The high-temperature gas inlet means may bedisposed in such a manner that an opening thereof for discharging thehigh-temperature gas is formed so as to discharge the high-temperaturegas toward a given location inside the gas exhaust pipe member, forexample, a location at which a valve unlikely to be heated easily ismounted.

Moreover, the present invention provides a solid product removalapparatus for removing a solid product stuck to the inner face of thegas exhaust pipe member, which is characterized in that a scrapingmember means is disposed inside the gas exhaust pipe member so as to beslidably movable in the gas exhaust pipe member along the lengthwisedirection thereof and which can scrape the solid product stuck to theinside of the gas exhaust pipe member.

In addition, the present invention provides an exhaust gas processingsystem for use in the preparation of semiconductors, which ischaracterized by a semiconductor manufacturing apparatus having a vacuumchamber for processing the semiconductors therein, a vacuum pump fordischarging gas for use in the vacuum chamber from the vacuum chamber, awet-type exhaust gas abatement device for processing the exhaust gasdischarged from the vacuum pump to turn it into a non-hazardous gas, afirst pipe member connecting the semiconductor manufacturing apparatusto the vacuum pump, a second pipe member connecting the vacuum pump tothe exhaust gas abatement device and extending a connecting portion tobe connected to the semiconductor manufacturing apparatus in a verticaldirection, and a solid product removal apparatus disposed at theconnecting portion of the second pipe member extending in the verticaldirection for removing the solid product formed upon reaction of theexhaust gas with moisture from the wet-type exhaust gas abatement deviceand stuck on the inner face of the connecting portion, wherein the solidproduct removal apparatus has substantially the same construction as thesolid product removal apparatus for removal of the solid product in thegas exhaust pipe member as described above.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

FIG. 1 is a view showing an example of a construction of an exhaust gasabatement device for carrying out a method for preventing an adherenceof a solid product in the gas exhaust pipe member in accordance with thepresent invention.

FIG. 2 is a view showing another example of a construction of an exhaustgas abatement device for carrying out a method for preventing anadherence of a solid product in the gas exhaust pipe member inaccordance with the present invention.

FIG. 3 is a view showing an example of a construction of an apparatusfor preventing the adherence of a solid product in the gas exhaust pipemember in accordance with the present invention.

FIG. 4 is a view showing an example of a construction of an apparatusfor preventing the adherence of a solid product in the gas exhaust pipemember in accordance with the present invention.

FIG. 5( a) is a conceptual view showing a conventional apparatus with aheater wound on an outer side of a gas exhaust pipe member.

FIG. 5( b) is a conceptual view showing an apparatus for flowing aninert gas having a high temperature into a gas exhaust pipe member inaccordance with the present invention.

FIG. 6 is a view showing an example of a construction of a wet-typeexhaust gas abatement device with the solid product removal apparatusfor removing a solid product in the gas exhaust pipe member inaccordance with the present invention.

FIG. 7 is a view showing an example of a construction of a solid productremoval apparatus in accordance with the present invention mounted onthe wet-type exhaust gas abatement device of FIG. 6.

FIG. 8 is a view showing an example of a construction of a solid productremoval apparatus in accordance with the present invention having theconstruction similar to the apparatus of FIG. 7.

FIG. 9 is a view showing a further example of a different constructionof a solid product removal apparatus in accordance with the presentinvention.

FIG. 10 is a view showing a further example of a different constructionof a solid product removal apparatus in accordance with the presentinvention.

FIG. 11 is a view showing another example of a construction of awet-type exhaust gas abatement device with the solid product removalapparatus in accordance with the present invention.

FIG. 12( a) is a view showing an example of a construction of a solidproduct removal apparatus for removal of a solid product in the gasexhaust pipe member in accordance with the present invention.

FIG. 12( b) is a view showing a solid product removal apparatus, similarto FIG. 12( a), which is provided with one rinsing water inlet pipemember.

FIG. 12( c) is an illustration showing a state of the formation of asolid product without solid product removal apparatus provided.

FIG. 13 is a view showing an example of the disposition of a tip openingof a rinsing water inlet pipe member in the solid product removalapparatus in accordance with the present invention.

FIG. 14 is a view showing an example of rinsing work with the solidproduct removal apparatus of FIG. 12( a).

FIG. 15 is a view showing a further example of a construction of awet-type exhaust gas abatement device provided with a solid productremoval apparatus for removal of the solid product in the gas exhaustpipe member in accordance with the present invention.

FIG. 16 is an illustration showing an example of a construction of thesolid product removal apparatus of FIG. 15.

FIG. 17 is a view showing an exhaust gas processing system for asemiconductor manufacturing apparatus.

PREFERRED EMBODIMENTS OF THE INVENTION

The present invention will be described in more detail by way ofembodiments with reference to the accompanying drawings.

FIG. 1 is a view showing an example of the construction of an exhaustgas abatement device for carrying out a method for preventing anadherence of a solid product in a gas exhaust pipe member in accordancewith the present invention. In FIG. 1, reference numeral 1 stands for anexhaust gas abatement device for removing a hazardous ingredient from anexhaust gas containing an ingredient forming a solid product and thehazardous ingredient. The exhaust gas abatement device 1 is providedwith a main pipe member 2 through which exhaust gas EG flows, and theexhaust gas EG flown into an inlet la of the main pipe member 2 passesthrough the main pipe member 2 and is introduced into a reaction section3 where hazardous ingredients containing a solid product are to beremoved.

The reaction section 3 may be of any type, whether it is of a dry typewith a reagent for adsorption of a hazardous ingredient filled thereinor it is of a wet type capable of removing a hazardous ingredient byexposure of exhaust gas to water or it is of a burning type or it is ofa catalyst-reactive type, or it may be of a type combining one with theother. The main pipe member 2 may be formed so as to allow ahigh-temperature inert gas having a high temperature to flowtherethrough via an inert gas inlet pipe member 5 from ahigh-temperature inert gas source 4 to prevent adhesion of the solidproduct to the inner wall of the main pipe member 2 by heating the innerwall of the main pipe member 2 with the high-temperature inert gas. Inthe example of the construction as shown in this drawing, the main pipemember 2 is provided with a temperature sensor 6 composed of athermocouple or the like, and a temperature measurement value with thetemperature sensor is subjected to feed-back to the high-temperatureinert gas source 4 to control the inner temperature inside the main pipemember 2 to a given temperature at which no solid product sticks.However, the high-temperature inert gas source 4 can also be set inadvance to a given fixed temperature in accordance with conditions forusage of the exhaust gas abatement device 1, without using such afeed-back control.

FIG. 2 is a view showing another example of the exhaust gas abatementdevice in accordance with the present invention. As shown in FIG. 2, theportions provided with the same reference numerals as in FIG. 1 indicatethe portions identical thereto or corresponding thereto. The same arealso be applied to the other drawings. Reference numeral 7 stands for abypass pipe member having a bypass valve 8, and the bypass pipe member 7is connected to the main pipe member 3 at an inlet (upstream) side ofthe reaction section 3 and to the main pipe member 2 at an outlet(downstream) side of the reaction section 3. The bypass pipe member 7has a role for flowing the exhaust gas EG through the bypass pipe member7 by opening the bypass pipe member 8 as problems such as a rise ofpressure due to clogging in the main pipe member 2 or at the reactionsection 3 with ingredients contained in the exhaust gas EG. In theexample of the construction as shown in FIG. 2, the main pipe member 2at the inlet side and the outlet side of the reaction section 3 isprovided with valves 9 and 10, respectively. Therefore, the reactionsection 3 can be subjected to maintenance upon an occurrence of troublesin the manner as described above by closing and stopping these valves.

In the example of the construction of FIG. 2, an inert gas having a hightemperature can be flown to the bypass pipe member 7 and the main pipemember 2 through branched inert gas inlet pipe members 5 and 5′,respectively. As the bypass pipe member 8 is closed, the inert gasintroduced into the bypass pipe member 7 is allowed to flow into themain pipe member 2 at the upstream side to block entry of exhaust gasinto the bypass pipe member and prevent a solid product from adhering tothe bypass pipe member.

FIG. 3 shows another example of introduction of a high-temperature inertgas into the bypass pipe member 7. In this example, the high-temperatureinert gas G can be blown onto the bypass pipe member 8 from ahigh-temperature inert gas inlet pipe member 11 to heat the inner wallof the bypass pipe member 7 therewith and also heat the bypass pipemember 8 to a sufficiently high temperature, thereby making it possibleto prevent a solid product from adhering to the bypass pipe member 8.

As shown in FIG. 4, the main pipe member 2 is provided with a branchpipe member 12, and a pressure gauge 13 is mounted at the tip of thebranch pipe member. The pressure gauge 13 can sense a state of cloggingof the main pipe member 2 with a solid product stuck in the main pipemember by measuring the pressure in the main pipe member. As shown inthis drawing, the branch pipe member 12 is provided with thehigh-temperature inert gas inlet pipe member 11 connected to thehigh-temperature inert gas source 4 so as to blow a high-temperatureinert gas onto the pressure gauge 13 to purge the exhaust gas enteringinto the branch pipe member 12 and at the same time heat the pressuregauge 13, thereby making it feasible to prevent adhesion of the solidproduct thereto.

As shown in FIG. 5( a), the conventional apparatus is constructed insuch a manner that a heater 16 is wound on the outside of the main pipemember 2 made by SUS, for example, and uses the method that the mainpipe member 2 is heated (by heating energy Q2) from the outside with theheater 16. Therefore, a heat-radiating energy Q1 becomes so high that aheating efficiency becomes too low. On the other hand, the apparatusaccording to the present invention is constructed in such a manner thatthe high-temperature inert gas G is flown through the inside of the mainpipe member 2 made by SUS, for example, and the main pipe member isheated from the inner wall thereof (as shown in FIG. 5( b)) so that theapparatus according to the present invention has a heat-radiating energyW lower than that of the conventional one. Therefore, the apparatusaccording to the present invention can heat the inside of the pipemember efficiently.

FIG. 6 is a view showing an example of the construction of the wet-typeexhaust gas abatement device provided with the solid product removalapparatus in accordance with the other example of the present invention.As shown in this drawing, the wet-type exhaust gas abatement device 1has a similar structure to the system as described above, which iscomposed of the main pipe member 2 through which an exhaust gas flows,the reaction section 3, and an exhaust pipe member 16 (a downstreamportion of the main pipe member) through which to flow the exhaust gasthat was rendered non-hazardous.

The reaction section 3 may be of a liquid-dispersing type in which anexhaust gas is exposed to water in a form of mist, moisture or the like,or of a gas-dispersing type in which exhaust gas is dispersed inreserved water and passed therethrough or of a type in which these typesare combined together. As is similar to the examples as described above,the high-temperature inert gas can be introduced in the main pipe member2 through the inert gas inlet pipe member 5 from the high-temperatureinert gas source 4. In addition, rinsing water can be introduced fromthe rinsing water source 18 through a rinsing water inlet pipe member20.

For the wet-type exhaust gas abatement device 1 having theabove-mentioned construction, a humidity within the main pipe member 2becomes so high at the position immediately in front of the reactionsection 3 that, in the case where the exhaust gas to be processedcontains an ingredient that may form a solid product upon reaction withwater, the solid product is likely to be formed, adhere to and depositon the portion immediately in front of the reaction section 3 of themain pipe member. In this embodiment, however, the solid product can beeffectively removed by flowing rinsing water through the portion fromthe rinsing water inlet pipe member 20. As the rinsing water, there maybe used water or an agent. Further, adherence and deposit of the solidproduct can be prevented by introducing the high-temperature inert gasinto the main pipe member 2 through the inert gas inlet pipe member 5from the high-temperature inert gas source 4 in substantially the samemanner as described in the examples on the basis of FIGS. 1 to 5.

For the wet-type exhaust gas abatement device as shown in FIG. 6, theinside of the main pipe member 2 is provided with a detector means 14composed of a thermocouple or the like for detecting a state of theadherence of a solid product stuck to the inner wall face of the mainpipe member 2. An amount of the rinsing water supplied from the rinsingwater source 18 can be controlled on the basis of the detection resultsof the detector means 14. The detector means 14 may be composed of apressure detector of a type capable of detecting pressure in the mainpipe member 2 or a photosensor of a type capable of detecting a state ofadherence of a solid product adhering to the inner wall face of the mainpipe member 2. The detector means 14 may be mounted at any optionalposition as long as it can monitor the state of the adherence of thesolid product in the main pipe member 2.

Further, the wet-type exhaust gas abatement device as shown in FIG. 6 isprovided with a temperature sensor 15 composed of a thermocouple or thelike at an optional position on the downstream side from the inert gasinlet pipe member 5 of the main pipe member 2. A flow rate of thehigh-temperature inert gas to be introduced into the main pipe member 2from the high-temperature inert gas source 4 can be controlled on thebasis of the output of the temperature sensor 15, thereby controllingthe inner temperature of the main pipe member 2 to a given temperaturethat can facilitate drying of the inner wall of the main pipe member 2.It is to be noted herein, however, that a temperature sensor of thistype is not always needed and that heating with the high-temperatureinert gas from the high-temperature inert gas source 4 can be controlledon the basis of a state of use of the wet-type exhaust gas abatementdevice or a state of introduction of rinsing water. Moreover, as theheating means for drying the inner wall face of the main pipe member,there may be used, for example, a variety of means, including but beingnot limited to means for winding a heater about the outer face of themain pipe member.

FIG. 7 illustrates an example of the specific construction for supplyingrinsing water to the main pipe member 2 from the rinsing water inletpipe member 20 as shown in FIG. 6. The rinsing water inlet pipe member20 is provided with a nozzle 31 having a plurality of rinsing waterspray holes at the tip thereof to spray rinsing water in a shower formtowards the inner wall face of the main pipe member 2 from the rinsingwater source 18. In the apparatus capable of preventing the adherenceand deposit of a solid product with rinsing water, it is preferred thatrinsing water to be fed into the main pipe member is allowed to flow inthe same direction as the flow direction of the exhaust gas in the mainpipe member leading to a reactor of the exhaust gas abatement devicefrom the vacuum pump. In the example as shown in FIG. 7, a connectingportion of the main pipe member 2 connecting to the reactor 3 isdisposed extending in a vertical direction, and the nozzle 31 isdisposed so as to allow the rinsing water to feed downward in theconnecting portion thereof. Therefore, the rinsing water can be flowndownward as in the direction identical to the flow passage of theexhaust gas in the connecting portion thereof.

FIG. 8 shows another example of the construction for the supply ofrinsing water into the main pipe member. In this example, the tip of therinsing water inlet pipe member 20 is connected to a rinsing waterjacket member 32 disposed on the outer periphery of the main pipe member2, and the rinsing water fed to the rinsing water jacket member 32 canbe fed to the inner wall of the main pipe member through a number ofrinsing water spraying holes (not shown) disposed through the pipe wallof the main pipe member 2.

FIG. 9 illustrates a further example of the construction for the supplyof rinsing water into the main pipe member 2. In this example, a rinsingwater jacket member 32 is disposed at the outer periphery of the mainpipe member 2 and a plurality of nozzles 33 communicating with therinsing water jacket member 32 are provided in the main pipe member 2.The rinsing water is fed to the rinsing water jacket member 32 throughthe rinsing water inlet pipe member 20 from the rinsing water source 18,and the rinsing water is then fed to the main pipe member 2 from thenozzles 33 and allowed to flow along the inner wall face of the mainpipe member.

FIG. 10 is a view showing another example of the construction of therinsing water inlet pipe member of the wet-type exhaust gas abatementdevice with the solid product removal apparatus in accordance with thepresent invention. In this example, the main pipe member 2 is providedwith a coating 34 made of a resin material on the inner face thereof.The coating makes it difficult for a solid product to adhere to theinner wall of the main pipe member 2, and at the same time for waterdrops of rinsing water to remain on the inner wall of the main pipemember 2 after rinsing with the rinsing water. Further, an introductionportion 35 of the main pipe member 2 toward the reaction section 3 isconnected to the reaction section 3 in a diagonal direction in order todecrease deposit ion of a solid product to be washed away and flown withthe rinsing water on the introduction portion 35. This construction issuitable for the case, for example, where the reaction section 3 is madeof a resin material or where the pipe member cannot be heated to a hightemperature.

FIG. 11 is a view showing another example of the construction of thewet-type exhaust gas abatement device provided with the solid productremoval apparatus in accordance with the present invention. In thisexample, the rinsing water inlet pipe member 20 is connected to theinert gas inlet pipe member 5 before introduction into the main pipemember 2. This construction can introduce the rinsing water into themain pipe member 2 after being heated to a high temperature with thehigh-temperature inert gas. Heating the rinsing water to a hightemperature in the manner as described above can dissolve the solidproduct stuck to the inner wall of the main pipe member 2 with therinsing water at a high temperature and remove it promptly.

FIG. 12( a) illustrates another example of means for feeding rinsingwater to the main pipe member 2, as shown in FIGS. 7 and 9.

In the example as shown in FIG. 12( a), a first rinsing water inlet pipemember 20 and a second rinsing water inlet pipe member 20′ are connectedto each other at a position spaced at a given interval in the axialdirection of the main pipe member 2 leading to the reactor 3 of thewet-type exhaust gas abatement device. The means for feeding the rinsingwater into the main pipe member 2, as shown in FIGS. 7 to 9, is providedin order to rinse off a solid product D (as shown in FIG. 12( c)) stuckin a gas-liquid interface I formed in the main pipe member close to thereactor 3 in the manner as described above. Basically, as shown in FIG.12( b), a rinsing water feed hole is provided at a position close to thetop end of the solid product D stuck therein. In this case, the solidproduct D can be rinsed off, however, a fresh solid product D1 (as shownin FIG. 12( b)) may also be caused to adhere under supply of the rinsingwater at an upstream side (at an upper position) (of the main pipemember 2) from the position at which the rinsing water is fed. The solidproduct D1 can be turned into a size smaller than the solid product Drinsed off with the rinsing water, but it is preferable to remove alsothe fresh solid product D1. The example as shown in FIG. 12( a) isconstructed in such a manner that such a fresh solid product as thesolid product D1 can also be removed.

In the rinsing work according to this example, the rinsing water is fedat a given periodical interval from the first rinsing water inlet pipemember close to the reactor 3, and the solid product D deposited on theinner face of the main pipe member close to the gas-liquid interface Ican be rinsed off. On the other hand, the second rinsing water inletpipe member 20′ disposed at the upper position far apart from thereactor 3 than the first rinsing water inlet pipe member 20 can feedrinsing water at a longer periodical interval than the first rinsingwater inlet pipe member 20 (that is, the rinsing water can be fed withthe second rinsing water inlet pipe member 20′ at every one time per agiven number of times of the feeding of the rinsing water with the firstrinsing water inlet pipe member 20), and the total period of time forfeeding the rinsing water needed for the rinsing work by the secondrinsing water inlet pipe member 20′ can be rendered shorter than thetotal period of time for feeding the rinsing water needed for therinsing work by the first rinsing water inlet pipe member 20.

Even by feeding the rinsing water with the second rinsing water inletpipe member 20′ in the manner as described above, another solid productD2 may be adhering to and deposit on the inner face of the main pipemember at the upstream side from the position of feeding the rinsingwater. The amount of the adhering solid product D2 is considerablysmaller than the amount of the solid product D1 produced by the firstrinsing water inlet pipe member 20, so that the deposit of the solidproduct D2 in such a smaller amount can be removed. Therefore, ifrinsing water inlet pipe members having equivalent actions are providedon the main pipe member in a spaced apart relation in a verticaldirection thereof, an amount of finally remaining adhered solid product,which corresponds to the solid product D2 as in the above-mentioned casewhere two rinsing water inlet pipe members are disposed, can be reducedin a manner of geometric series. More specifically, it is appropriatethat, for instance, an amount, a frequency of introduction of rinsingwater with each rinsing water inlet pipe member, and so on, aredetermined by an amount of a solid product deposited on the inner faceof the main pipe member. At this end, an amount of the solid productdeposited on the inner face of the main pipe member may be detected bymethods including but being not limited to a method for determining anamount of the solid product in response to the results of detection witha sensor mounted for detecting an amount of the solid product depositedat a given position in the main pipe member or a method for determiningan amount of the solid product under conditions fixed in advance inaccordance with the status of operations of the reactor or the like. Asolubility of some solid products in water may be temperature-dependent,and solubility in water of many of them may increase as the temperaturearises. Examples of such solid products include, but are not limited to,a reaction product, HBO₃, resulting from a reaction between BCl₃ andwater and a reaction product, Si₂, resulting from a reaction betweenSiC₄ and water. It is preferred, therefore, to elevate the temperatureof the rinsing water for these solid products, but the elevation of thetemperature of the rinsing water, however, may rather increase thepossibility of forming a solid product in the vicinity of a portion atwhich the rinsing water is being fed. The cause for this may be due toan increase in a velocity of the reaction with a gaseous ingredient withthe rinsing water for forming a solid product due to a rise in thetemperature of the rinsing water. Therefore, in order to decrease theformation of such solid products, it is preferred that the temperatureof the rinsing water in the vicinity of the top edge of the rinsingwater on the inner face of the main pipe member be decreased to thelowest possible level, while the rinsing water as a whole is kept at ahigh temperature. With these points taken into account, in the exampleas shown in FIG. 14, the rinsing water can be fed in a temperaturedistribution as described above by feeding rinsing water H having ahigher temperature from the first rinsing water inlet pipe member 20 andrinsing water C having a lower temperature from the second rinsing waterinlet pipe member 20′.

The rinsing water inlet pipe member is mounted on the main pipe memberin the vicinity of an inlet of the reactor 3 for the wet-type exhaustgas abatement device in the manner as shown in FIG. 12( a), and a gascontaining BCl₃ was subjected to processing experiments (Experiments #1,#2 and #3) for rinsing a solid product adhering to the inner face of themain pipe member under conditions as will be described below.

(Conditions of Gas)

-   Flow Rate of Gas: 10 slm-   Concentration of BCl₃: 10%    (Conditions of Feeding Rinsing Water)-   Feeding Interval:    -   Experiment #1: No rinsing water fed.    -   Experiment #2: Feeding for 10 seconds and ceased feeding for 5        minutes and 50 seconds (1 cycle=6 minutes)    -   Experiment #3: Feeding for 10 seconds and ceased feeding for 5        minutes and 50 seconds (1 cycle=6 minutes)-   Feeding Modes:    -   Experiment #2: the rinsing water inlet pipe member 20 only was        used.    -   Experiment #3: In one cycle, feeding 9 times from the rinsing        water inlet pipe member 20 and then feeding once from the        rinsing water inlet pipe member 20′.-   Amount of Feeding:    -   Experiment #2: 2.4 liters per minute    -   Experiment #3: 2.4 liters per minute (total amount)-   Period of Experiment: 120 minutes

After the completion of the experiments, powdery materials stayed at theportion leading from the main pipe member to the reactor was dissolved,and the concentration of boron (B) in water was measured to determine anamount of an adhering solid product as H₃BO₃. The following tableindicates the results of the above experiments.

Gas Inlet Portion Inner Face of Main Pipe Member of Reactor Experiment#1 0.01 gram  5.1 gram Almost clogged Experiment #2 0.93 gram 0.02 gramThe solid product was adhering in a large amount between two rinsingwater inlet pipe members. An almost half of the pipe member was clogged.Experiment #3 0.03 gram 0.01 gram The solid product was adhering in asmall amount on the upper portion of the rinsing water inlet pipemember. The state of the pipe member was substantially the same asbefore the experiment.

In the above examples, two rinsing water inlet pipe members 20 and 20′are provided designing so as to cause the rinsing water inlet pipemember on the upstream side of the main pipe member to remove the solidproduct derived by the introduction of the rinsing water from therinsing water inlet pipe member at the downstream side thereof. It isfound therefrom, however, that the relationship of the positions of therinsing water inlet pipe members is not limited to this embodiment andthat, in summary, in order to allow the solid product formed by therinsing water fed previously, adhering and deposited to be removed, therinsing water to be fed later is fed such that the top end thereof onthe inner face of the main pipe member reaches above the top end of thesolid product formed beforehand.

For instance, when description is made taking the example as shown inFIG. 12, the second rinsing water inlet pipe member 20′ may be mountedat a position lower than the first rinsing water inlet pipe member.Moreover, if it is possible to feed the rinsing water in a manner so asto satisfy the conditions described above, it is not needed to providethe rinsing water inlet pipe members in a vertically spaced apartrelationship in plural stages along the main pipe member. In otherwords, the rinsing water inlet pipe member can be disposed in a singlestage (that is to say, a rinsing water inlet pipe member is disposed ata single position of the main pipe member), and the rinsing action canbe done in substantially the same manner as described in the aboveexamples by changing the pressure of feeding the rinsing water.

When the rinsing water is fed into the main pipe member through therinsing water inlet pipe member, it is preferred that the location ofthe inner face of the main pipe member where it becomes wet with the fedrinsing water due to scattering of the rinsing water upon striking ontothe inner face of the main pipe member does not expand upwardly above agiven location. It is preferred, therefore, that the tip opening 21 ofthe rinsing water inlet pipe member 20 be disposed in a directiontangent to the inner face of the main pipe member 20, as shown in FIG.13. Moreover, it is preferred that the tip opening 21 be disposed so asto be directed horizontally or downwardly, not upwardly, from the pointof view of preventing the rinsing water from scattering or controllingthe maximal height of the fed rinsing water on the inner face of themain pipe member (controlling the position of the top edge thereof). Therinsing water discharged from the tip opening 21 into the inner face ofthe main pipe member flows downward on the inner face of the main pipemember while circulating around the central axial line of the inner facethereof under a centrifugal force. The maximal height at which therinsing water can reach on the inner face of the main pipe member can bedetermined by the flow speed of the rinsing water flowing downward.Therefore, in the case where the rinsing water inlet pipe member isdisposed in a single stage in the manner as described above,substantially the same effects can be achieved by controlling the flowspeed of the rinsing water as the rinsing action is carried out bymounting the rinsing water inlet pipe members in plural stages in themanner as described above.

FIG. 15 is a view showing an example of the construction of the wet-typeexhaust gas abatement device with the solid product removal apparatusaccording to another example of the present invention. As shown in FIG.15, the wet-type exhaust gas abatement device 1 has substantially thesame structure as those described above, which is composed of the mainpipe member 2 through which to flow exhaust gas, the reaction section 3,and the gas discharging pipe member 16 through which to flow anon-hazardous exhaust gas. The main pipe member 2 is designed insubstantially the same manner as described above to introduce ahigh-temperature inert gas from the high-temperature inert gas source 4through the inert gas inlet pipe member 5 to control the formation of asolid product in the main pipe member. In this example, in additionthereto, a solid product removal means 40 for scraping the solid productstuck to a portion of the main pipe member 2 at the reactor 3 isprovided at the portion of the main pipe member 2 in substantially thesame manner as described above.

A specific construction of the solid product removal means 40 isillustrated in FIG. 16. As shown in this drawing, the solid productremoval means 40 may be composed of a drive means 42 such as a motor orthe like, disposed at the top end of a pipe member portion 2′ extendingvertically from the reactor 3 of the main pipe member 2 and a scrapingmember means 44 disposed so as to be movable vertically in the pipemember portion 2′ by the drive means for scraping the solid productstuck on the inner face of the pipe member portion. The scraping membermeans may be of any type that can scrape the solid product by sliding onthe inner face of the pipe member portion 2′, and it may include but isnot limited to a type in the form of a disc, spiral, bar or the like ora type capable of rotating in addition to moving vertically.

In this drawing, reference numeral 46 stands for a rinsing water inletpipe member so disposed as to rinse off the solid product adhering tothe scraping member means 44 and the inner face of the pipe memberportion 2′ by appropriately feeding rinsing water into the pipe memberportion 2′. In FIG. 15, reference numeral 14 stands for a detector meansfor detecting a state of the adherence of the solid product adhering tothe inner wall face of the pipe member portion 2′ by detecting thepressure within the main pipe member. Reference numeral 15 stands for atemperature sensor for controlling the high-temperature inert gas source4.

INDUSTRIAL APPLICABILITY

Although the present invention is particularly suitable for a gasexhaust system of a semiconductor manufacturing apparatus, it is to beunderstood that it is not limited to the gas exhaust system thereof andit can be applied to a variety of gas exhaust systems.

1. A solid product removal method for removing a solid product adheringto an inner face of a gas exhaust pipe member, characterized in that themethod comprises the steps of: rinsing off a primary solid productformed upon reaction of an ingredient contained in exhaust gas with amoisture present in the gas exhaust pipe member and adhering to theinner face of the gas exhaust pipe member by feeding a primary rinsingwater to the primary solid product; and rinsing off a secondary solidproduct formed newly upon reaction with the primary rinsing water andadhering to the inner face of the gas exhaust pipe member at an upstreamside from the position at which the primary rinsing water is fed byfeeding a secondary rinsing water to the secondary solid product in thegas exhaust pipe member, wherein the gas exhaust pipe member is providedwith a first rinsing water supply inlet and a second rinsing watersupply inlet; wherein said first and second water supply inlets arespaced apart at a given interval along a direction of flow of exhaustgas; the primary rinsing water is fed from the first rinsing watersupply inlet; the secondary rinsing water is fed from the second rinsingwater supply inlet, the second rinsing water supply inlet is disposed atthe upper position than the first rinsing water supply inlet, and thesecondary rinsing water is fed at a longer periodical interval than theprimary rinsing water.
 2. The solid product removal method according toclaim 1, wherein the secondary rinsing water has a lower temperaturethan that of the primary rinsing water.